cc: Fix data race in cc::TaskState::IsFinished.

cc/tiles/tile_task_manager.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/tiles/tile_task_manager.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/trace_event.h"
 
 namespace cc {
@@ skipping 28 matching lines @@
 
 void TileTaskManagerImpl::CheckForCompletedTasks() {
   TRACE_EVENT0("cc", "TileTaskManagerImpl::CheckForCompletedTasks");
   Task::Vector completed_tasks;
   task_graph_runner_->CollectCompletedTasks(namespace_token_, &completed_tasks);
 
   for (auto& task : completed_tasks) {
     DCHECK(task->state().IsFinished() || task->state().IsCanceled());
     TileTask* tile_task = static_cast<TileTask*>(task.get());
     tile_task->OnTaskCompleted();
+    tile_task->DidComplete();
   }
 }
 
 void TileTaskManagerImpl::Shutdown() {
   TRACE_EVENT0("cc", "TileTaskManagerImpl::Shutdown");
 
   // Cancel non-scheduled tasks and wait for running tasks to finish.
   TaskGraph empty;
   task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
   task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);
 
   raster_buffer_provider_->Shutdown();
 }
 
 RasterBufferProvider* TileTaskManagerImpl::GetRasterBufferProvider() const {
   return raster_buffer_provider_.get();
 }
 
 }  // namespace cc